This invention relates to the technology for commercialization of composite fiber materials and particularly to the highly moisture-absorptive fiber excellent in moisture absorptivity and moisture permeability, capable of being freely knitted or woven, and having good touch and feeling.
As substitute fiber materials for natural fiber, various kinds of fibers including regenerated fibers such as rayon, semi-synthetic fibers such as acetate, and synthetic fibers such as polyurethane, nylon, polyester, acryl, polyethylene and polypropylene have conventionally been in popular use. However, these fiber materials were all inferior in moisture absorptivity and moisture permeability as well as in touch and feeling to the natural fiber, even in case of the polyurethane being a synthetic fiber material having a relatively excellent moisture absorptivity and moisture permeability.
For this reason, there is an idea that a composite fiber material obtained by pulverizing natural leather to the particle size capable of passing through the 50 to 250 mesh sieve, mixing and kneading these particles with synthetic resin such as nylon and vinyl acetate and spinning the mixture into filaments should be used to improve the moisture absorptivity and touch.
However, mixing and kneading of natural leather powder with synthetic fiber material led to the poor spinning performance due to the adverse influence exerted on the spinning machine such as occurrence of clogging because the synthetic fiber becomes lacking in flexibility, poorer in elongation characteristics and thus liable to break. Moreover, the natural leather powder to be mixed and kneaded with the synthetic fiber material has a particle size only enough to pass through the 50 to 250 mesh sieve, the fiber must be designed to be considerably thick as compared with general fibers, thus resulting in "thick, hard and fragile" one. Furthermore, such composite fiber material was not applicable to actual textile products and was thus of little practical use because it is slow in moisture absorbing and desorbing speed, though its water-holding performance is improved.